Playtests: Encountering Difficulties

So as a designer, I have a problem. In a game where a large part of your score is “how long you survived”, I need some assurance that the game-time is finite. That eventually, no matter how good a fight they put up, the player will lose eventually, and the game will come to an end. Stasis is my enemy. If the player can find a way to force a permanent stalemate, they have effectively won in a way that invalidates everyone else’s scores. Their ability to get a high score is then only bounded by their patience, meaning that my game has transformed into a flashy version of Desert Bus.

So to make sure that doesn’t happen, I need to make sure that stasis is never reached. And one of the easiest ways to do that is to gradually shift the game rules. This gives me two advantages. First, if they have found something that works, then as I shift the rules, there is a good chance that it will stop working at some point. (Provided I’m shifting the right rules at least.) Second, I can use it to effectively put a cap on game time by shifting towards something that is, for all intents and purposes, impossibly hard.

Tetris is a classic example of a game that uses this. (Particularly the impossibly hard part.) It gradually gets more difficult by making pieces fall faster. At some point, the pieces are falling fast enough that it is not even physically possible to move them to the edges of the board before they hit the bottom. At this point, the game is effectively over. The player can, if high enough skill, put off the inevitable for a little bit, but the writing is on the wall. The game is going to end.

So too in Boss Rush. The little red ships eventually gain homing missiles as an upgrade. If they survive long enough, this gives them the ability to hit you from just about anywhere on the screen. This is important to me for balance, since it is my only real defense against strategies that involve bugging out my ship AI by trapping it in a corner somewhere where it can’t hit you. (I have far more faith in players’ abilities to abuse my AI than I do in my own ability to foresee all such gimmicks and plan against them.)

However, here is where playtesting gave me some interesting insights. It turns out that, while players don’t mind being hit by missiles if the little ship got them through power ups, they detest having the ship start out with missiles. This feels completely unfair, and they generally feel (fairly correctly, really) that the game is effectively over, but for the screaming.

“Huh”, I said. “That’s problematic. I really kind of need ships to start getting missiles, as part of the difficulty curve.” So as an experiment, instead of letting the ships start with better weapons, I instead cranked up the spawn rate of ship power ups. It becomes somewhat absurd now, with powerups pretty much pouring from the sky in curtains, like some kind of weapon-improving raindrops. The ships still get missile upgrades pretty quickly.

And yet… It works. Players (at least the ones I tested with) don’t seem to mind this nearly as much, even though the net result is the same. Some theories as to why:

Since it’s a familiar scenario (little ship vs. big ship) changing the little ship starting loadout feels like it’s breaking the metaphor. We’ve all played shmups before, and we know, the reward for being blown up isn’t starting up again with full powerups. It’s being kicked back down to weakling level, and having to claw our way back up. So maybe this implicit break in the expected structure is jarring?

Having the ships collect items feels like there is more agency involved. It is still theoretically possible for you to stop them, or at least delay them from getting enough to hit missiles. And if you can kill them before they get the missiles, then they have to start over. So even though it’s hard, it presents the players with more of a feeling of “I have a chance”?

The abruptness of the spike. While missiles are only level 3 out of 5 possible power ups, they represent a significant increase in danger level. Players tended to not care as much about ships starting with more guns, but once they started with missiles, it suddenly felt like they were on borrowed time.

The two step process “it’s raining powerups” -> “he has missiles now, oh crap I’m dead” is better for the anticipation than just jumping straight to the “crap, missiles” stage of the game.

I’m still not completely sure what the exact motivation is here. I still don’t feel like I completely understand what is going on in my testers’ heads. (Which, I suppose, is why I’m running playtests in the first place…) It might be different for each person, and might not be any of these. Even so though, I think I can draw at least a couple of useful lessons from the experience that I should keep in mind in the future.

A slim chance that is almost impossible feels better to players than zero chance.

Anticipation and telescoping are good. (Valve talked about this at GDC this year in fact. Hearing “rumblerumblerumble” and going “oh crap, incoming tank” is a more memorable experience than just “Surprise! Tank!”)

Attacks that are very difficult to dodge are acceptable as a punishment (you didn’t do XXX so now he gets to attack you with YYY) but not as an unavoidable part of a game.